1. Field of the Invention
This invention relates, generally, to trim components for lapboard siding systems used on the exteriors of residential and commercial buildings. More particularly, it relates to trim pieces that are co-extruded from wood-plastic composites and polyvinyl chloride.
2. Description of the Prior Art
Clapboard siding is a type of lapboard siding made from boards which have one edge thicker than the other, and which are designed to be applied to the exterior of a frame structure in a horizontal format where each board—other than the bottom board—overlaps an immediately adjacent board below. Clapboard siding, which has a very distinctive and aesthetically pleasing appearance, is most commonly associated with frame homes built in the New England region of the United States. In Australia and New Zealand, this type of siding is known as weatherboard, and was extensively used in forested regions from the Colonial period to the mid-20th Century. In other venues, it is referred to as bevel or lap siding.
The individual boards used for clapboard siding are known as clapboards. Historically, clapboards were made by radially splitting a log about its longitudinal axis. In fact, the word “clapboard” comes from the Dutch infinitive klappen, which means “to split.” As more sophisticated equipment became available, clap boards were made by turning a log on a large lathe to a uniform diameter and, then, radially sawing it.
When clapboards are applied as siding, they are layered like shingles and nailed to an underlying frame structure of the building, with the thin side of each clapboard lying under the thick edge of the clapboard on top. Gravity and the overlapping design of the siding protected the underlying structure from the weather by encouraging rain and snow to run down the outside of the structure to the ground, rather than penetrate the siding where it could cause rot and decay. In addition, the overlapping design also allowed the individual clapboards to expand and contract with changes in humidity and temperature. Clapboards may be left unfinished, or they may be painted to accommodate personal taste. Over the years, many types of timber have been used to make clapboard siding. Though natural weather-resistant and pest-resistant qualities have made red cedar a popular choice for centuries, other soft and hard woods can be used as well.
Due to the increasing scarcity of large-diameter, old-growth timber, the rapidly-escalating cost of lumber, and concerns about the ethics of using large amounts of wood for building construction, clapboards today are increasingly made of materials other than sawn timber. Clapboards may be made of fiberglass-reinforced concrete, cementitious materials, water-resistant medium-density fibreboard (MDF), or composites of wood fibers and thermoplastic resins. Many of these materials have greater durability and longevity than wood, making them a better choice for harsh climates. As these clapboards made from manmade materials have imitation wood-grain texture, once they are installed and painted, they are difficult to distinguish from clapboard siding made from sawn lumber. The appearance of clapboard siding can also be achieved using formed laminar sheets of aluminum or polyvinyl chloride. Though nowhere near as durable as solid clapboards and trim made from other manmade materials, formed sheet siding has a definite cost advantage over their solid counterparts. The disadvantages to formed sheet siding are a significantly-reduced appearance of authenticity when viewed up close, greatly reduced durability and—at least with respect to vinyl siding—greatly reduced adhesion of paint. In spite of these disadvantages, aluminum and metal siding is used extensively on starter homes and on other structures where minimization of cost is a priority. Indeed, it is probably true that the popularity of aluminum and vinyl siding for low-end structures has diluted the appeal of well-executed clapboard designs.
Board-and-batten siding is another popular type of lapboard siding. With a board-and-batten siding system, boards are installed in a vertical, abutting format, and the joints between adjacent boards are covered with narrower, secondary boards called battens. The same manmade materials used to manufacture modern clapboards can be used to manufacture the boards and battens used in board-and-batten siding systems. More importantly, at least in the context of the present invention, is the fact that the same trim components can be used for either clapboard siding or board-and-batten siding. Trim components include door and window framing elements, inside and outside corner elements, aprons, frieze boards, gable frieze boards, soffit and fascia components, and other components that are used to hide cut ends of the lap siding boards, frame various types of openings, and provide specialized visual effects. Though not considered lapboard siding, large-panel siding can also be used with the trim components of the present invention. Panels for these types of systems are typically manufactured in three standard sizes: 4 ft. by 8 ft. (1219 mm×2438 mm), 4 ft. by 10 ft. (1219 mm×3048 mm) and 4 ft. by 12 ft. (1219 mm×3657 mm) plywood or waferboard sheets that are generally about 11 mm thick, and are typically engraved with vertical grooves to give the appearance of individual abutting wood slats. The panels typically have tongue and groove edges, which fit together and form a joint having the appearance of one of the many engraved vertical grooves in the panels. Such siding is typically used to reduce labor and material costs for basic, low-end, utilitarian housing. Porta-Camp® frame housing units, mobile homes, and modular homes are notorious for this type of siding.
For conventional lapboard siding systems, including clapboard, as well as board-and-batten siding systems, the siding is applied directly to the exterior of a frame structure, which has been covered, first, with plywood or waferboard sheathing and then, with a water-impermeable or water-resistant membrane (hereinafter “weather barrier”) such as tar paper, plastic-coated paper, or a polymeric film. Typically, there is no spacing between the siding boards and the weather barrier. With clapboard siding, the top edge of each horizontally-disposed clapboard is in contact with the weather barrier, thereby creating cavities of triangular cross section along the length of each board. Once paint has been applied to the siding, these cavities may become partially sealed from the exterior. With board-and-batten siding systems, the entire rear surface of each of the vertically-disposed boards is in contact with the weather barrier. Large panel siding provides unique opportunities for cost cutting, as each siding panel also functions as a sheer panel, thereby enabling a builder to completely forego the use of underlying sheathing. In essence, the panels are both the sheathing and the siding, and are typically either nailed or stapled directly to the framing, which has been wrapped with a weather barrier. This method of construction is about as cheap as it gets. As a general rule, the only time that flashing is used to deflect water from the structure is when the siding meets a lower horizontal trim piece. The flashing is typically nailed to the sheathing beneath the siding and extends over the trim piece with a downward bent edge piece so that water cannot pool and enter the joint between the siding and the trim piece.
In spite of the benefits and inherent attractiveness of conventional lapboard siding systems, there are a number of problems associated with those systems. Some of the problems are merely cosmetic; others can affect the structural integrity and longevity of the structure to which the siding is applied; still others have both cosmetic and structural implications.
Likely the most significant problem associated with conventional siding systems, and with conventional lapboard siding systems, in particular, is the passage of water through the joints in the siding. Even though the siding is designed for water runoff, wind can easily drive water uphill, as well as drive it horizontally to vertical a joint. In board-and-batten siding systems, the water can wicks between the siding and the weather barrier. In clapboard siding systems, water can collect in partially-sealed cavities above the clapboards. Unfortunately, the weather barrier is never waterproof because the attachment of the siding mandates that the barrier be perforated by thousands screws, staples, or nails. Every perforation is a potential leakage point to the underlying sheathing. Furthermore, vertical overlapping seams of the weather barrier material are seldom sealed. Thus, water that wicks between the siding and the weather barrier can also wick between the overlapping seams to the underlying sheathing. Once the water has wicked to the outer surface of the sheathing, which is, almost invariably, a wood-based product, it has no way of quickly escaping or evaporating, so it is gradually absorbed by the wood component of the sheathing. Absorption of water by the sheathing sets the stage for rot and decay of that material. Rot and decay can be accelerated by mold growth. Worse, yet, is the reality that moist lumber attracts termites and carpenter ants. Colonies of these pests can destroy the structure of a frame building in short order. Over time, structural damage to the stud framing beneath the sheathing is inevitable, along with a concomitant reduction in the effectiveness of the insulation installed between framing members. The damage to the underlying structure will eventually result in a loosening of the siding boards, trim components, appliques and other decorative features from the structure. In addition, if the siding boards and trim are made of wood or a water-absorbing wood product, rotting, swelling, and warping of the siding boards and trim components, will also occur. Cracks in associated masonry can also result. As a consequence of this inherent defect in the design of conventional lapboard siding systems, any structure built in a climate having both wind and rain (i.e., nearly every region of the U.S.) is, essentially, a throw-away structure, or at the very least, one which will require major structural renovation every fifty or so years. Though typically no underlying sheathing is employed in large-panel siding systems, water can wick between the panel and the weather barrier and, then, through overlapping seams in the barrier layer, to insulation installed between framing members, where it can begin to rot the framing members.
In regions of the country with little wind, clapboards are typically secured to the underlying structure by top nailing, which is also referred to as blind nailing. Nails used in blind nailing are driven through the clapboard near the upper edge thereof so that the nails on that clapboard will be covered by the lower edge of the next-installed clapboard directly above. Thus, each progressively higher clapboard overlaps the nails used to secure the immediately lower clapboard, thus rendering all nails, other than those on the topmost clapboard blind, or hidden from view. Blind nailing secures the clapboards to the underlying structure and provides an aesthetically pleasing appearance to the clapboard siding. However, with the only fastening mechanism being applied at the tops of the clapboards, the lower portion of each board is unsecured. In the presence of moderate or high winds, it is common for wind to lift the loser edges of the clapboards, causing the blind nails to loosen and bend, or even dislodge clapboards from the underlying structure. As a consequence of the potential for wind damage to clapboard siding, it is common to secure clapboards with blind (hidden) nails along the top edge of each board and face (exposed) nails along the lower portion of each board. The face nails are driven through the lower portion of one clapboard, through the upper edge of an overlapped, clapboard, through the weather barrier, and into the underlying sheathing layer. Though clapboards can be secured by blind nailing, conventional trim pieces associated with the clapboard siding must be face nailed to the underlying structure. It should be mentioned that with a board-and-batten siding system, though the boards may be blind nailed, the battens must be face nailed.
Though face nails provide additional strength to clapboard structure, they also introduce some additional new problems. One problem with face nailing is that it is considered by many to be unsightly. In order to mitigate the unsightly effect of face nailing, each face nail must be countersunk below the surface of the clapboard, the resulting depression caulked to a level even with the exterior surface of the clapboard, and the caulk compound painted along with the clapboard. In addition to being incredibly time-consuming, the caulking of each face nail creates long-term problems, primarily because the caulk seal deteriorates over time and the color of the paint over caulk changes at a rate different that of the paint over the clapboard material. The seal deteriorates over time because of differences in coefficients of expansion between the caulk and the clapboard material, a loss of resilience by the caulking compound over time due to damage sustained by exposure to ultraviolet light, heat, and an oxidizing environment. Once the caulk seal is breached, exposed wood grain in the countersunk depression can absorb water, causing the clapboard to swell around the face nail. In addition, the breach in the seal creates a leakage path around the nail head and through the nail hole into the sheathing. Expansion and contraction of the clapboards with changes in temperature and humidity can enlarge the nail holes in the clapboards, making them more than trivial sources of leakage. The problem of water seepage also afflicts older aircraft having wings made of wood that are covered with a waterproof layer of painted polyester fabric that functions much as siding on a building. Sheet metal flap seals are typically secured to the trailing edge of the wings with wood screws. It is extremely difficult (almost impossible) to prevent the entrance of moisture around the heads of the screws and into the wing structure. The entrance of moisture will invariably cause structurally-debilitating rot of the wing's trailing edge. The identical process of destruction occurs, over time, on a building with face nailed siding.
Another problem associated with clapboard siding systems is that the bottommost clapboard or starter strip contacts the foundation or wainscot. During rain or yard watering, water collects at the juncture of the juncture and wicks behind the boards, thereby increasing the likelihood that, over time, significant water damage will occur.
With some lap siding systems, clearance of at least two inches, between the roof and the lap siding system, may be required. Flashing and counter flashing may be installed and caulked to protect the gap from wind and water. However, this gap may be unsightly and, like the junctions discussed above, the caulk and flashing may fail so that water is able to seep behind the flashing and behind the siding.
Conventional lapboard siding systems rely heavily on caulking to secure the structure against water leakage and the problems associated therewith. Typically, joints between clapboards are caulked, as are junctures where planks terminate at other structural or decorative features, such as windows, doors, trim, or changes in the contour of the underlying structure. However, time has shown that a perfect and complete seal of a structure against the elements is impossible to achieve and, in fact, may exacerbate the problems associated with water leakage over time. The inventor believes that any attempt to seal a building against leakage of water into the frame structure will invariably fail while, at the same time, succeed in permanently trapping any water that breaches the “seal” so that it can affect maximum damage. The inventor also believes that conventional, unbreathable lapboard siding systems, which leave no continuous vertical gap between the underlying framed structure and the siding and siding trim components, and which use extensive amounts of caulking compound in an failed attempt to seal out moisture from the structure, unnecessarily shorten the life expectancy of not only the structure but, very likely, that of each of those who dwell in the structure, by potentially exposing them to mold.
As heretofore described, moisture can penetrate the exterior shell of a “sealed” structure in a number of ways, including through the face nail holes in the siding, through joints between lapboards, through trim transitions, and through seams and nail holes in the weather barrier. Once moisture is trapped behind the weather barrier, the opportunity for it to evaporate is severely limited, as airflow in a well-built frame structure is virtually non-existent. If moisture is leaking behind the weather barrier faster than it can evaporate, eventual destruction of the building is assured.
Accordingly, a need exists for a lap siding and trim system that avoids unsightly junctures of elements, that, with very few exception, scrupulously avoids face nailing, and which does not require the application of caulking. Furthermore, a need also exists for a lapboard siding and trim system that can be installed flush with the roof.
The soffit and fascia trim systems of conventional lapboard siding systems have historically been the most time-consuming and complicated aspects of the siding installation process, particularly when these regions of the building are desirably waterproofed and aesthetically pleasing. In the soffit and fascia region of the building, siding elements meet at a variety of angles and typically in small work areas that complicate the installers' efforts.